MediaWiki Wikibase extension: Deserialization of Untrusted Data
CVE-2026-103441 is a high-severity deserialization of untrusted data vulnerability in MediaWiki Wikibase extension from Wikimedia Foundation, with a CVSS 4.0 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. Affected MediaWiki Wikibase extension versions: 1.46; 1.45; 1.43. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.28% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of MediaWiki Wikibase extension you run against the affected versions below, and install the vendor's latest release.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| The Wikimedia Foundation | MediaWiki Wikibase extension | 1.46; 1.45; 1.43 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- LowA basic user account is enough.
- User interaction
- ActiveA user must deliberately do something unusual, such as dismissing a warning.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- LowLimited loss of availability on the vulnerable system.
- Confidentiality (other systems)
- HighSerious loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- HighSerious loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- LowLimited loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:N/AU:Y/R:I/V:C/RE:M/U:Red. Scored by CNA.
Official description
Deserialization of untrusted data vulnerability in The Wikimedia Foundation MediaWiki Wikibase extension allows Leverage Executable Code in Non-Executable Files. This issue affects MediaWiki Wikibase extension: 1.46, 1.45, and 1.43.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Deserialization of Untrusted Data vulnerabilities
- 7.2 High severity
- 8.1 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
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